73 lines
2.2 KiB
C++
73 lines
2.2 KiB
C++
/* ----------------------------------------------------------------------
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LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
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https://www.lammps.org/, Sandia National Laboratories
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LAMMPS development team: developers@lammps.org
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Copyright (2003) Sandia Corporation. Under the terms of Contract
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DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
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certain rights in this software. This software is distributed under
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the GNU General Public License.
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See the README file in the top-level LAMMPS directory.
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------------------------------------------------------------------------- */
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#include "compute_erotate_sphere.h"
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#include "atom.h"
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#include "error.h"
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#include "force.h"
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#include "update.h"
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using namespace LAMMPS_NS;
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static constexpr double INERTIA = 0.4; // moment of inertia prefactor for sphere
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/* ---------------------------------------------------------------------- */
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ComputeERotateSphere::ComputeERotateSphere(LAMMPS *lmp, int narg, char **arg) :
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Compute(lmp, narg, arg)
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{
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if (narg != 3) error->all(FLERR, "Illegal compute erotate/sphere command");
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scalar_flag = 1;
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extscalar = 1;
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// error check
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if (!atom->omega_flag) error->all(FLERR, "Compute erotate/sphere requires atom attribute omega");
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}
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/* ---------------------------------------------------------------------- */
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void ComputeERotateSphere::init()
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{
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pfactor = 0.5 * force->mvv2e * INERTIA;
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}
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/* ---------------------------------------------------------------------- */
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double ComputeERotateSphere::compute_scalar()
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{
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invoked_scalar = update->ntimestep;
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double **omega = atom->omega;
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double *radius = atom->radius;
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double *rmass = atom->rmass;
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int *mask = atom->mask;
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int nlocal = atom->nlocal;
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// sum rotational energy for each particle
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// point particles will not contribute, due to radius = 0.0
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double erotate = 0.0;
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for (int i = 0; i < nlocal; i++)
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if (mask[i] & groupbit)
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erotate +=
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(omega[i][0] * omega[i][0] + omega[i][1] * omega[i][1] + omega[i][2] * omega[i][2]) *
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radius[i] * radius[i] * rmass[i];
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MPI_Allreduce(&erotate, &scalar, 1, MPI_DOUBLE, MPI_SUM, world);
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scalar *= pfactor;
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return scalar;
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}
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